U.S. Pat. No. 3,958,303 owned by the assignee of the present invention relates to a single spindle vent removing machine in which a centering probe on the spindle is inserted into the vent to such a depth that the lower circular cutting edge of a cylindrical cutter which coaxially houses the probe can engage the meat surrounding the vent. By then applying vacuum pressure within the cutter against the outside of the posterior of the carcass, the skin at that portion of the carcass tends to be drawn up into the cutter to facilitate severance by the then rotated circular cutting edge.
While the mechanism of the '303 patent has performed well in carrying out its intended function, in some instances it may cause larger than desirable amounts of edible meat to be left around the vent "plug" which results after the vent has been fully severed from the carcass. Thus, there is a need for a vent remover which will remove the vent as safely, thoroughly, and expeditiously as the mechanism in the '303 patent, yet which leaves more of the edible portions of the carcass behind as the vent plug is removed.
U.S. Pat. No. 4,023,237 in the name of Pieter Meyn shows a complicated three spindle vent removing machine.